Esters of alpha-dichloromethyl benzhydrols and process



ESTERS F m-DICHLOROMETHYL BENZHYDROLS AND PROCESS W E Craig and ElwoodY. Shropshire, Philadelphia, Pa., and Harold F. Wilson, Moorestown, N.J., assignors to Rohm & Haas Company, Philadelphia, Pa., 21 corporationof Delaware 1 No Drawing. Application March 8, 1954, Serial No. 414,902

14 Claims. (Cl. 260-487) with positive chlorine and an acid RCOOH,preferably in an inert organic solvent, at reacting temperatures betweenabout 0 and about 120 C. Solvents such as carbon tetrachloride, ethylenedichloride, benzene, toluene, xylene, naphtha, ethers, and the like maybe used. If an ether such as ethyl ether or isopropyl ether is used,reaction temperatures should be kept relatively low, for example, belowabout 35 C. Dimethylformamide can also be used as a solvent if reactiontemperatures are below 50 C. It is preferred that the reaction system beanhydrous, in which case in the presence of inert organic solventsboiling above 80 to 90 C. the reaction temperature may be in the higherrange such as 90-120 C. and the reaction completed relatively rapidly.Yet the system need not be anhydrous, for if water is present goodresults are obtained by working below 50 C., preferably 0 to 0., eventhough reaction is then slow.

While no catalyst is necessary, the presence of an acidic agent such aszinc chloride or acetate, copper acetate, or other soluble heavy metalsalt accelerates the re- .action and is desirably used when the reactionis not spceded up by raising the temperature.

The reaction mixture is worked up by suitable steps. If salts arepresent, as from use of a catalyst or other inorganic reagent, themixture is filtered. If a water layer is present, it is taken off andthe reaction mixture dried. It is then stripped of solvent and excessacid under reduced pressure. Heating may be carried to 180 C. at 20 mm.pressure, for example. In many cases the product can be crystallized,particularly with the aid of a volatile solvent such as petroleum ether.In some cases, as with butyrates and chlorocarboxylates the productshave remained as oils.

As'source of positive chlorine'there is most advantageously used anorganic hypohalite, such as butyl hypochlorite. This and other alkylhypochlorites are prepared by reacting chlorine with a solution of analkali or alkaline earth hydroxide in the presence of an alcohol,

such as methyl, ethyl, propyl, butyl, or amyl alcohol.

The alkyl hypochlorites are peculiarly effective reagents United StatesPatent 0 Patented Jan. 8, 1957 (R' phenyl)2CI-ICHCl2 throughdehydrohalogenating with a strong base in the presence of an alcohol.The above compounds are readily prepared, for example, by the methoddescribed in U. S. Patent No. 2,464,600. Useful compounds of thisstructure include the bis(4-chlorophenyl)-, bis(4-fluor.ophenyl) bis4-bromophenyl) bis dichlorophenyl bis(methylchlorophenyl)-, ditolyl-,bis(ethylphenyl)-, bis(butylphenyl)-, bis(methoxyphenyl)-, etc.,.2,2-dichloroethanes to yield the corresponding 1,1-bisphenyl-2-chlorethylenes. There may be used a single isomer or a mixture ofisomers.

Dehydrohalogenation is conveniently accomplished by treating abisphenyldichloroethane with sodium or potassium hydroxide in thepresence of an alcohol, such as methyl, ethyl, propyl, or butyl alcohol,at to C. Excess alkali and salt formed are washed away with water andthe ethylenic compound obtained upon stripping. Compounds of this typehave previously been reported.

Typical preparations according to the process of this invention arepresented in the following illustrative ex- .arnples, wherein parts areby weight.

Example 1 217 parts. During this time the reaction mixture wasmaintained below 30 C. by cooling as needed. The mixture was stirred for24 hours at about 30 C. It was then filtered and the filtrate wasconcentrated under reduced pressure to give an oil, which was trituratedwith petroleum ether. The treated oil formed crystals, which wererecrystallized from nitromethane. The yield was 595 parts ofa-dichloromethyl14,4'-dichlorobenzhydryl formate. This compound meltedat lO5-107 C.

In place of the above bis(chlorophenyl)chloroethylene there may be usedother diphenylchloroethylenes having any of the above indicated phenylsubstituents, including fluorine, bromine, lower alkyl, and alkoxy. Twoor more of these substituents may be present in the same ring, as in1,l-bis(methylchlorophenyl)-2-chloroethylene. The reaction proceeds inthe same way and the products obtained are related in their action andutility.

Example 2 reaction mixture was stripped under reduced pressure andheated to about 180 C. at 25 mm. pressure. The

' product obtained was an oil, which could not be crystallized. Itcorresponds in composition to a-dichloromethyl- 4,4-dichlorobenzhydrylbutyrate. The yield was 74%.

Example 3 The procedure of Examples 1 and 2 was followed withsubstitution of chloroac'etic acid for the previous acids. The reactionmixture was stripped at about C. under reduced pressure to give an oil,which was distilled at -183 C./0.3 mm. The resulting product, obtainedin 62% yield, corresponds in composition toa-dichloromethyl-4,4-dichlorobenzhydryl chloroacetate.

-Examp le4 A mixture of 57 parts of 1,l-bis(4 chlorophe'nyl) 2 bonatesolution and with water. tilled off. The residual oil was taken up inabout 35 parts chloroethylene,z.49 parts of trichloroacetic acid, and157 parts o f,.tert:.hutyl ..alcohol .was stirred ..while .25. vparts.of

tert-butyl hypochlorite were added. The temperature rose to 37 C. duringthe addition. The reaction mixture was left standing forabout 16 hours."T he reaction mixture was heated under reduced pressure to removevolatile material. The residue ,was dissolved in benzene. The benzenesolution was washed with water. The benzene-layer wasthen subjected todistillation, benzene being removed to yield an oily residue, which onCooling and standing formed a glass. This was recrystallized from octaneto .yield awhite solid melting at ll3-l14.5

C. and corresponding by analysis to wdichloromethylrA dichlorobenzhydryltrichloroacetate.

By the same method 1,1-'bis(ethylphenyl)-2-chloroethyleue was reactedwith formic acid and tert-butyl hypochlorite to yield 1a-dichloromethyl-4,4'-diethylbenzhydryl .formate;1,1-bis(4-methoxyphenyl)-2-chloroethylene was reacted .with tert-butylhypochlorite and acetic acid to formwdichloromethyl-4,4-bismethoxybenzhydryl ace- -.tate;.andl,l-bis(chlorophenyl)-2-chloroethylene was reacted with formic acid andtert-butyl hypochlorite to form a dichloromethyl 4,4 dichlorobenzhydrylformate. In place of butyl hypochlorite otheralkyl hypochlorites can beused with like effect.

In place of these simple hypochlorites there may be used other sourcesof positive halogen. For example, 1,3-dichloro-5,S-dimethylhydantoin isan available and useful source of such halogen. There may similarly beused such compounds as tetrachlorobenzoguanimine, hexachloromelamine,trichloromelamine, azochlorarnide, di-

chloramine, chloramine, dichlorourea, dichlorodicyandiamide, etc.

Example 5 hours. The mixture wastreated with waterand benzene.

The benzene layer was washed with dilute sodium car- The benzene wasdisof isooctane and the product crystallized therefrom. It melted atll8.5-120.5 C. The product was recrystallized from nitromethane. Thethus purified product melted at129131 C. -By analysis this compound wasa-dichloromethyl-4A-dichlorobenzhydryl acetate.

Other organic sources of positive chlorine may be used in the same wayto give thedesired esters.

Example 6 There were mixed 65 parts of 1,1-diphenyl-2-chloroethylene and280 parts of glacial acetic acid. The 1,1-diphenyl-Z-chloroethylene hadbeen prepared by the method described above, starting with1,1-diphenyl-2,2-dichloroethane, heating it with sodium hydroxide in thepresence of methanol, washing away excess alkali and the salt formedduring this reaction, and recovering the resulting1,1-diphenyl-Z-chloroethylene. The above mixture was warmed to efiectsolution of the 1,1-diphenyl-2-ch1oroethylene. To this solution wasadded with stirring over a one hour period 38 parts of tert-butylhypochlorite. The temperature of the reacting mixture rose to 54 C. Thereaction mixture/was allowed to stand for 1.5 hours. The reactionmixture was then heated under reduced pressure and acetic acid wasdriven off. There was obtained as a residue an oily product. It wastaken up in about 75 parts of isooctane and product was crystallizedtherefrom. A yield of 75.5 parts of a white solid was obtained.Thisquantity corresponds to 81.5% of theory. This material correspondsclosely in composition with a-diChlOlO- methylbenzhydryl, acetate. Themelting point of this compound is 102.5-104 C.

When this compound .was used as the sole toxicant against twofispottedmites it gave. a kill of adults of 66% ate, silica, or other solidcarrier.

.ovicide.

The esters of this invention are interesting novel chemical substanceswhich have the peculiar property of being acari'cides. They have beenapplied to living plants intested with mites or spiders and-found to bedefinitely effective in .c ombatting these ,pests. Typical of -the ,dataobtained against two'spotted mites are the following, the first figuregiven being for the kill of adult mites and the secondfor'thezkilltofeggs at dilution of l :800:wdichloromethyl-4,4-dichlorobenzhydryl butyrate, 51% and19%; 0cdichloromethyl-4,4 dichlorobenzhydryl trichlorqacetate, 86% and 11%;a-dichloromethyl-4,4'-dichlorobenzhydryl chloroacetate; 58% and 23.a-dichloromethyl- 4,4-dichlorobenzhydryl acetate,:92% and 15%;a-dichloromethyl-4,4-diethylbenzhydryl formate, 89% and 15%, with theacetate thereof giving kills of 79% and 17%;e-dichloromethyl-4,4-dichlorobenzhydryl formate,

,a dichloromethyl 4,4-bismethoxybenzhydryl acetate,

90% and-20%.

Field testing with a-dichloromethyl-4,4-dichlorobcnzhydryl formatedemonstrated commercial control :of European red mite, and two-spottedmite on apple trees.

These compounds may be formulated with solider liquid diluents or,carriers. They may be used in the form of wettable powders, whereinwetting and dispersing agents are used along with clay. magnesiumcarbon- They may be extended with similar solid, carriers toform dusts.They may also be. dissolved in organic solvents along with oil-solubleemulsifiers to provide self-emulsifying concentrates. They may be.usedtogetheravith insecticides and/or fungicides.

We claim:

1. A process for. preparing a-dichloromethylbenzhydryl esters ofsaturated, lower aliphatic monocarboxylic acids which comprises reactingby bringing together at a ,reacting temperature between 0 and C.anethylenic compound of the structure positive chlorine, and an acidR"COOH,'R being a member of the class consisting of hydrogen, fluorine,chlorine, bromine, alkyl groups of not over four carbon atoms, and themethoxy group, and R" being a member ofthe class consisting of hydrogenand alkyl and chloroalkyl groups of not over three carbon atoms.

2. A-process for preparing esters of a-dichloromethylbenzhydrol andsaturated, lower aliphatic monocarboxylic acids which comprises reactingby bringing together at a reacting temperature between 0 and 120 C. acompound of the structure (R' phenyl)zC=CI-IC1, an alkyl hypochlorite ofnot over five carbon atoms, and an acid R 'cOOl-l, R .being a member ofthe class consisting of hydrogcn, fluorine, chlorine, bromine, alkyl,groups of; not over four carbon atoms, and the methoxy group, and Rbeinga-member of the class consisting'of hydrogenand alkyl andchloroalkyl groups of not over -three carbon atoms.

3. The process. of claim 2 wherein an inert organic solvent is present.

4. A process for preparing esters of a-dichloromethylbenzhydrol andsaturated, lower aliphatic monocarboxylic acids which comprises reactingby bringing together at a reacting temperature from 90 to 120 C. in ananhydrous system a compound of the structure (R phenyl)zC=CI -IC1 analkyl hypochlorite of not overfive carbon atoms, and

an. acid RV COOI-L Rbeingamember of the class consisting of hydrogen,fluorine, chlorine, bromine, alkyl groups ofnot'over four carbon atoms,and the' methoxy group, and-R"' beingarnembcrof the class consistingofhydrogen, and alkyl and chloroalkyl groups of not over three carbon,atoms.

5. A process according to claim 4, wherein the hypochlorite istert-butyl hypochlorite.

6. A process for preparing a-dichloromethyl-4,4'-dichloromethylbenzhydryl formate which comprises reacting by bringingtogether at a reacting temperature between and 120 C.1,1bis(chlorophenyl)-2-chloroethylene, tert-butyl hypochlorite, andformic acid.

7. A process for preparing a-dichloromethyl-4,4-dichloromethylbenzhydrylacetate which comprises reacting by bringing together between 0 and 120C. 1,1-bis(chl0- rophenyl)-2-chloroethylene, tert-butyl hypochlorite,and acetic acid.

8. A process for preparing a-dichloromethyl-4,4-diethylbenzhydrylformate which comprises reacting by bringing together between 0 and 120C. 1,1-bis(ethylphenyl)- 2-chloroethylene, tert-butyl hypochlorite, andformic acid.

9. A process for preparing a-dichloromethyl-4,4'-dichlorobenzhydrylchloroacetate which comprises reacting by bringing together between 0and 120 C. 1,1-bis(chlorophenyl)-2-chloroethylene, tert-butylhypochlorite, and chl'oroacetic acid.

10. Compounds of the formula (R' phenylhG-OHO]:

000R where R is a member of the class con'sistitng of hydrogen,fluorine, chlorine, bromine, alkyl groups of not over four carbon atoms,and the methoxy group, and R" is a member of the class consisting ofhydrogen and alkyl and chloroalkyl groups of not over three carbonatoms.

11. A compound of the formula (C1 phenyl)zO-OHClz 12. A compound of theformula (01 phenyl)2GCHCl2 0 0 C CH;

13. A compound of the formula (C2115 phenyIhC-GHCh 14. A compound of theformula (01 phenylhC-OHCI:

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Chen et al.: J. Am. Chem. Soc. 72, 5124-5 (1950). Pepper etal.: J. Am. Chem. Soc. 72 (1950), p. 1417. March et al.: J. Entomol.(1952), pgs. 851-3.

10. COMPOUNDS OF THE FORMULA